System for use of land fills and recyclable materials

ABSTRACT

Gases are vented from a waste site such as a landfill, and the gases are separated into at least three streams comprising a hydrocarbon stream, a carbon dioxide stream, and residue stream. At least a portion of the carbon dioxide stream and hydrocarbon stream are liquefied or converted to a supercritical liquid. At least some of the carbon dioxide gas stream (as a liquid or supercritical fluid) is used in a cleaning step, preferably a polymer cleaning step, and more preferably a polymer cleaning step in a polymer recycling process, and most preferably in a polymer cleaning step in a polymer recycling system where the cleaning is performed on-site at the waste site.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the use of gas within land-fill sites,the recycling of materials from recycling collection and separation, andthe recycling or commercial use of waste effluents materials fromland-fills.

2. Background of the Art

A significant societal effect caused by the unceasing growth in worldhuman population is the increased use of a limited supply of rawmaterials. Both in the field of agricultural and the field of commercialproducts, an increasing population requires an increasing expenditure ofenergy and use of material to sustain even the existing average lifestyle. As desires and expectations are growing around the world withinevery population center for higher standards of living, there is amulti-faceted draining effect on resources. Increased productioncapacity has been able to sustain this growth for centuries, but eventhe most optimistic technologist must appreciate that there is a finitelimit to growth and production given the closed system of the Earth.

Recycling has been one direction of increased effort in reutilization ofmaterials to conserve dwindling original supplies. Initially, recyclinginvolved the wholesale reuse of objects, such as beverage containerswhere return fees or deposits were placed on the containers, the feeswere returned to the purchaser with return of the containers, and thecontainers were cleaned and returned into the production line to berefilled. The limitations on this system included at least the factsthat the containers would show unacceptable levels of wear fairly earlyduring repeated reuse (especially with bottles that could be easilyscratched or chipped), containers had to be returned to individualoriginal suppliers according to brand names (which dictated against anycentralized system), and cleaning was difficult as different co-wasteswere added to the containers (e.g., cigarette stubs and filters) and fewviable cleaning processes could remove some of the associated wasteswithout extensive manual labor.

One of the more successful recycling programs has involved the recyclingof aluminum beverage containers. The success has been accomplishedbecause of some unique attributes in the specific product. The materialitself (the aluminum) is easily melted and placed back into the naturalmanufacturing stream. Associated materials in the product (e.g., inks,coating materials, lid adhesives, and the like) are easily removed fromthe aluminum by the heating needed to melt the aluminum (and withpossible solvent treatment), and solid wastes added to the aluminumcontainers can be removed by physical processes (e.g., shredding of cansand washing/flotation) alone or in combination with the melting stepsneeded for recycling. This model, however, does not translate well toother materials, as the properties, economics, technology and market foraluminum are unique, and it is this uniqueness that enables success ofthe system.

Certain classes of polymeric materials are presently recycled incommercial systems relying in great part on collection of polymericcontainers from residential and commercial sites. This system iscomplicated in that associated wastes with differing sources ofpolymeric materials may not be amenable to a single format of treatment.Although local jurisdictions may require some level of cleaning of thepolymeric containers, the original liquids or powders may beinsufficiently removed from the polymer. These materials may vary fromwater, beverages, detergents, oils, alkaline cleaners, and highly toxicmaterials, including pesticides. In addition, the containers may containlabels that are applied by adhesives of different strengths, and thelabel stock itself may need to be treated by distinct processes. Asingle cleaning process has been unlikely to act on all polymericcontainers, at least in part because of the deficiencies in the cleaningsteps that fail to provide a sufficiently pure supply of polymer thatwould enable direct recycling.

Recycling of motor oil containers is illustrative of the problem. Motoroil containers typically are high-density polyethylene (HDPE) whichlends itself well to recycling if it is sufficiently clean. However,residual oil coating the interior surface of the “empty” motor oilcontainers constitutes a contaminant that prevents use of the containersas high grade plastics. Based upon measurement of samples of used motoroil containers, this residual oil coating appears to average 4.6 percentof the weight of the used plastic container and can represent as much as20 percent of the container weight. Estimates are that over one billionone-quart plastic containers were filled with motor oils in the UnitedStates in 1993. If 4.6 percent by weight of those containers is motoroil, the one billion empty plastic containers represent approximately160 million pounds of plastic and over 7 million pounds of motor oilthat could be recovered for reuse if an appropriate separation methodwere available. However, because the motor oils have not been easilyseparated from the plastic containers, the vast majority of thesecontainers are currently disposed of in landfills, leaking oils into thesoil and groundwater, and occupying significant landfill volume.

Current available options to landfilling the waste plastics include (a)grinding the containers and using them in other plastic recyclingprocesses on a very limited (dilute) basis; (b) using an aqueous processto displace the oil from the plastic; (c) using a halogenated solvent todissolve/dilute the oil; or (d) using a combustible or flammable solventto dissolve/dilute the oil from the plastic.

The problems with these options are as follows:

-   -   a. Existing recyclers in the United States can blend limited        quantities of oil contaminated plastics in recycled plastic        products. Large quantities cannot be blended because of the        undesirable effects of the residual oil on the recycled plastic        properties. Examples include “plastic lumber” and lower grade        plastic products.    -   b. Aqueous processes can be used to displace the oil from the        plastic. However, detergents and/or surfactants are required to        assist displacement of the oils. A stream of usable oil-free        plastic will be generated by this method; however, the displaced        oil will be contaminated or changed chemically and additional        processing will be needed to separate it from the aqueous        solutions. The aqueous solutions themselves will be a secondary        waste stream that will require treatment before being recycled        or discharged as waste water.    -   c. Halogenated solvents can be used to dissolve/dilute the oils        from the plastic. Again, usable plastic will be obtained by this        process if the solvents do not extract essential components from        the plastic. The halogenated solvent solutions will require        distillation to recover the oils and recycle the solvents. In        general, it is difficult to fully reclaim usable oil from the        distillate. Furthermore, many halogenated solvents are ozone        depleting compounds and potential health hazards to humans, and        therefore their use and release into the environment are under        regulation and close scrutiny by federal and state governments.    -   d. Combustible or flammable solvents may be used to dissolve        and/or displace the oil from the plastic. Usable plastic can be        generated by this method if the solvents do not extract        essential components from the plastic. The combustible or        flammable solvent solutions will require distillation to recover        the oils and recycle the solvents. Only distillation equipment        suitable for combustible or flammable solvents may be used and        even then fire safety concerns will be significant. As in the        case of the use of halogenated solvents, the oil may not be        fully recoverable from the distillation.

The methods described above can provide some usable plastic fromoil-contaminated plastics. However, they will provide usable oil only atthe expense of a secondary waste stream that itself will requiretreatment and additional expense. The recycling of plastic and oil from“empty” plastic oil containers presents serious environmental and wastestream disposal problems if conventional organic or aqueous solvents areused for the separation of the plastic and oil. Discarding of thecontainers as landfill waste also presents environmental problems inthat the residual oil may eventually leach into soil and groundwater.

Landfills provide the most complex issue to be faced in the entire realmof waste disposal, with the possible exception of long-term storage ofnuclear wastes. Landfills are little more than holes in the ground intowhich massive volumes of wastes are dumped, compacted and covered, withan unsupported expectation that the material will eventually decomposeand be absorbed into the normal ecology. This expectation is unsupportedbecause excavations of earlier (19^(th) and early 20^(th) century)landfills have found that even paper products, including newspapers, aresubstantially intact (if not structurally pristine) over a time periodwhere decomposition had been expected. Present attempts to moderate theimpact of landfills have met limited environmental and limited economicsuccess.

The typical landfill reclamation attempts have included providing gasvents into the covered masses of landfilled materials, separating outthree streams of gas, the streams usually distinguished along the linesof highly volatile organic streams including methane, carbon dioxide,and commercially unsuitable mixtures of gases. The separations can beperformed by various techniques selected from amongst semi permeablemembranes, filtering membranes, differential condensation, differentialabsorption, differential solvency absorption, molecular sieves andcombinations of these technologies. The non-commercial gases are oftenvented and flared directly in the atmosphere. The volatile hydrocarbongas can be liquefied and used for fuels, usually with onsitecondensation of the hydrocarbon gas. (The stream usually comprises atleast or only methane. In some uses, other low carbon hydrocarbons suchas ethane and some propane may be included in the hydrocarbon gasstream, in a separate stream, or in the waste stream, but these otherhydrocarbons are usually removed as part of the residue gas stream. Thehydrocarbon gas has been used for pipeline natural gas or compressednatural gas for vehicles. The carbon dioxide has also been liquefied,but has found few commercial outlets of sufficient volume as to makethat product stream economically supportive of the recycling process.Part of the reason is the hesitancy of the largest volume of commercialuse of carbon dioxide (carbonated beverages) to use carbon dioxidesourced from landfill waste streams in their products. The firstmanufacturer to use this source of carbon dioxide would be quicklyattacked in the market by its competitors, even though the carbondioxide greatly exceeds the purity required by the industry.

U.S. Pat. No. 5,279,615 discloses a process for cleaning textiles usingdensified carbon dioxide in combination with a non-polar cleaningadjunct. The preferred adjuncts are paraffin oils such as mineral oil orpetrolatum. These substances are a mixture of alkanes including aportion of which are C₁₆ or higher hydrocarbons. The process uses aheterogeneous cleaning system formed by the combination of the adjunctwhich is applied to the textile prior to or substantially at the sametime as the application of the densified fluid. According to the datadisclosed in U.S. Pat. No. 5,279,615, the cleaning adjunct is not aseffective at removing soil from fabric as conventional cleaning solventsor as the solvents described for use in the present invention asdisclosed below.

U.S. Pat. No. 5,316,591 discloses a process for cleaning substratesusing liquid carbon dioxide or other liquefied gases below theircritical temperature. The focus of this patent is on the use of any oneof a number of means to effect cavitation to enhance the cleaningperformance of the liquid carbon dioxide. In all of the disclosedembodiments, densified carbon dioxide is the cleaning medium. Thispatent does not describe the use of a solvent other than the liquefiedgas for cleaning substrates. The combination of ultrasonic cavitationand liquid carbon dioxide may be well suited to processing complexhardware and substrates containing extremely hazardous contaminants.

U.S. Pat. No. 5,377,705, issued to Smith et al., discloses a systemdesigned to clean parts utilizing supercritical carbon dioxide and anenvironmentally friendly co-solvent. Parts to be cleaned are placed in acleaning vessel along with the co-solvent. After adding super criticalcarbon dioxide, mechanical agitation is applied via sonication orbrushing. Loosened contaminants are then flushed from the cleaningvessel using additional carbon dioxide.

U.S. Pat. No. 5,417,768, issued to Smith et al., discloses a process forprecision cleaning of a work piece using a multi-solvent system in whichone of the solvents is liquid or supercritical carbon dioxide. Theprocess results in minimal mixing of the solvents and incorporatesultrasonic cavitation in such a way as to prevent the ultrasonictransducers from coming in contact with cleaning solvents that coulddegrade the piezoelectric transducers.

U.S. Pat. No. 5,888,250 discloses the use of a binary azeotropecomprised of propylene glycol tertiary butyl ether and water as anenvironmentally attractive replacement for perchlorethylene in drycleaning and degreasing processes. While the use of propylene glycoltertiary butyl ether is attractive from an environmental regulatorypoint of view, its use as disclosed in this invention is in aconventional dry cleaning process using conventional dry cleaningequipment and a conventional evaporative hot air drying cycle.

U.S. Pat. No. 6,200,352 discloses a process for cleaning substrates in acleaning mixture comprising carbon dioxide, water, surfactant, andorganic co-solvent. This process uses carbon dioxide as the primarycleaning media with the other components included to enhance the overallcleaning effectiveness of the process. There is no suggestion of aseparate, low pressure cleaning step followed by the use of densifiedfluid to remove the cleaning solvent. As a result, this process has manyof the same cost and cleaning performance disadvantages of other liquidcarbon dioxide cleaning processes. Additional patents have been issuedto the assignee of U.S. Pat. No. 6,200,352 covering related subjectmatter. Liquid carbon dioxide is usually the cleaning solvent.

U.S. Pat. No. 6,558,432 describes a textile cleaning system thatutilizes an organic cleaning solvent and pressurized fluid solvent isdisclosed. The system has no conventional evaporative hot air dryingcycle. Instead, the system utilizes the solubility of the organicsolvent in pressurized fluid solvent as well as the physical propertiesof pressurized fluid solvent. After an organic solvent cleaning cycle,the solvent is extracted from the textiles at high speed in a rotatingdrum in the same way conventional solvents are extracted from textilesin conventional evaporative hot air dry cleaning machines. Instead ofproceeding to a conventional drying cycle, the extracted textiles arethen immersed in pressurized fluid solvent to extract the residualorganic solvent from the textiles. This is possible because the organicsolvent is soluble in pressurized fluid solvent. After the textiles areimmersed in pressurized fluid solvent, pressurized fluid solvent ispumped from the drum. Finally, the drum is de-pressurized to atmosphericpressure to evaporate any remaining pressurized fluid solvent, yieldingclean, solvent free textiles. The organic solvent is preferably selectedfrom terpenes, halohydrocarbons, certain glycol ethers, polyols, ethers,esters of glycol ethers, esters of fatty acids and other long chaincarboxylic acids, fatty alcohols and other long-chain alcohols,short-chain alcohols, polar aprotic solvents, siloxanes,hydrofluoroethers, dibasic esters, and aliphatic hydrocarbons solventsor similar solvents or mixtures of such solvents and the pressurizedfluid solvent is preferably densified carbon dioxide.

To make landfills better able to service the environment and to assistin the recycling of materials not added to the landfill mass, differenttechnologies, processes and business models are needed.

SUMMARY OF THE INVENTION

Gases are vented from a waste site such as a landfill, and the gases areseparated into at least three streams comprising a hydrocarbon stream, acarbon dioxide stream, and a residue stream. At least a portion of thecarbon dioxide stream and hydrocarbon stream can be liquefied orconverted to a supercritical liquid. New uses of the effluent gasstreams are desirably found within the economic Environment and localphysical environment of the waste site, and preferably physically withinor adjacent to the waste site to improve the economic performance of thesystem. At least some of the carbon dioxide gas stream (as a liquid orsupercritical fluid) may be used in a cleaning step, preferably apolymer cleaning step, and more preferably a polymer cleaning step in apolymer recycling process, and most preferably in a polymer cleaningstep in a polymer recycling system where the cleaning is performedpreferably on-site at the waste site or in direct pipeline connection tothe carbon dioxide source in the waste site. Hydrocarbon gas may be usedat least in part to generate energy at the site (e.g., by burning tocreate heat/thermal energy, to drive a motor or engine, or to generateelectricity), provide a hydrogen fuel source, provide carbon black andthe like.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows a block diagram of a sited recycling, reclamation and usecenter according to one practice of the present invention.

FIG. 2 shows a block diagram of a generic sited production, reclamationand use center according to one aspect of the invention.

FIG. 3 shows a typical land fill gas (LFG) collection system.

FIG. 4 shows a simplified schematic of a gas turbine that may be used ata site of the present invention.

FIG. 5 shows a schematic drawing of a carbon dioxide recovery system.

FIG. 6 shows a schematic of another unique apparatus and processdescribed herein.

DETAILED DESCRIPTION OF THE INVENTION

One aspect of the present invention is to provide a more economicallyviable system associated with landfills. In the absence of greatereconomic benefits to the owners and investors in landfills, the abilityof landfills to assist in actual waste reduction is limited. It istherefore necessary to associate additional technologies to existing andfuture landfill sites and or MRFs (material recovery facility) to assuremaximum use of the materials at the site that can be used in subsequentcommercial processes. This use of available resources includes theaddition of commercial systems to the recycling sites and the use ofeffluent gases in existing and developing commercial processes. The factthat in most jurisdictions recycling and landfill sites are closelyaligned can assist in the improvement in landfill utilization, as therecycled materials (e.g., paper, plastic, and metals such as aluminumand steel) and the waste material (for the landfill) are already broughtto a common area. For the purpose of this invention, a common site or asite shall be considered an area wherein collected gases can betransported without accessing or establishing non-piped (that is,transportation by means other then pipes and tubes that involvedseparate containerizing of gases and physical transport of thecontainers) substantial gas transportation systems for one or more ofthe gas products. For example, typical sites would have no more than aten mile (18 km) distance separating gas venting from gas collection andgas compression and compressed gas (e.g., gas, liquid or supercriticalliquid) from commercial process use and transport the gases over thatdistance through pipes and tubes.

Gases are vented from a waste site such as a landfill, and the gases areseparated into at least three streams comprising a hydrocarbon stream, acarbon dioxide stream, and residue stream. In a preferred practice ofthe invention, at least a portion of the carbon dioxide stream andhydrocarbon stream are liquefied or converted to a supercritical liquid.In a preferred embodiment, at least some of the carbon dioxide gasstream (as a liquid or supercritical fluid) is used in a cleaning step,preferably a container cleaning steps, such as a polymer or metalcleaning step, and more preferably a polymer cleaning step in a polymerrecycling process, and most preferably in a polymer cleaning step in apolymer recycling system where the cleaning is performed on-site at thewaste site. The cleaning step may also be used in cleaning of“electronic waste,” that is electronic equipment such as telephones,computers (PC's, Mac's, lap tops, hand-held, etc.), pagers, radios,VCR's, CD players, televisions, DVD players and other devices that maycontain chip boards. The cleaning step may be used for any wastematerial that has organic or metal contaminants.

Particularly desirable and commercially effective on-site uses include,but are not limited to at least partially energy-independent processes(energy being provided by burning of a portion or all of the hydrocarbongas stream to provide heat or ultimately electricity), carbon dioxidebased cleaning processes, polymer recycling (especially including acarbon dioxide-based cleaning step), dry ice manufacture, and the like.Commercially available equipment is marketed that enables electricalgeneration from hydrocarbon gases (referred to as Gen-sets in thetrade), often using boiler systems that are powered by combustion of thegas and drive generators. Commercial dry ice systems are available, andaccording to the present invention, those dry ice systems could bepowered on site by electricity provided by burning of the hydrocarbongases.

There are a number of related aspects of the invention that can be usedseparately or combined in various proportions to practice benefits ofthe present invention.

One aspect of the invention would require the performance of steps onsite (within 18 km of the collections site or waste site where gases aregenerated) that enhance the economic benefits of maintaining andoperating a landfill system, as opposed to merely providing a landfillsite. Among the individual specific tasks that can be performed on siteat the waste system could include one or more of the following, which isnot intended to be totally inclusive. Such ancillary tasks, in additionto capturing the two primary revenue potential gas streams (e.g., thehydrocarbon stream and carbon dioxide stream), would include hydrogenproduction, carbon black production, carbon dioxide liquefaction, andother value enhancing material production processes directed towards aneffluent stream. One attempt at this type of technology is discussed ina paper relating to an Acrion Technologies, Inc. business plan for theproduction of methanol from landfill gas.http://www.netl.doe.gov/publications/proceedings/97/97ng/ng97_pdf/NGP4.PDFprovides the complete business plan document. This limited disclosure isspecific to energy use in methanol production.

Preferred technologies for use of on-site developed energy from thehydrocarbon gas stream from the landfill gas (LFG) include energy forcompression of the gas streams, transport of the gas streams and othermaterials, electrolysis of water to produce hydrogen and oxygen incapturable forms at high purity, catalytic treatment of the gas streamsto produce carbon black and/or hydrogen (e.g., see “Hydrogen fromNatural Gas without Release of CO₂ to the Atmosphere” Gaudernack, Bjornand Lynum, Stynar, 1996, Proceedings of the 11^(th) World HydrogenEnergy Conference, Stuttgart, Germany, HYDROGEN ENERGY PROCESS XI, pages511-23 and Hydrogen Power: Theoretical and Engineering Solutions, Hox,Ketil et al., 1998 Kluwer Academic Publishers, Netherlands, pp. 143-148,which references are incorporated herein by reference in their entiretyfor the disclosure of carbon black generation processes and hydrogengeneration processes from hydrocarbon gas streams. Additional backgroundinformation on reformation of hydrocarbons is provided by U.S. Pat. Nos.5,648,582; 6,254,807; 6,402,989; 6,409,940; 6,458,334; and 6,488,907.These processes are specifically among the processes that can be usedon-site or in piped connection to collected gases from thegas-generation sites as part of the practice of technologies within thescope of the present invention. The use of other known processes incombination with these processes can provide synergy with the individualprocesses or to the entire economic strategy. For example, infrared orultraviolet treatments can be used in conjunction with the cleaningprocesses, and some of the energy for those treatments can be providedby burning gas streams or by exchanging gas streams with a separatecommercial energy source for other available energy (e.g., electricity).

A preferred embodiment of a landfill gas processing facility of thepresent invention is generally indicated at 10 in FIG. 1. The landfillgas processing facility is preferably located near a landfill such thatthe transportation of landfill gases from the landfill to the facilityis accomplished by means of a direct piping system without firstcompressing the landfill gases or having to truck the landfill gasesfrom the landfill to the facility. Alternatively, it is also within thescope of the present invention to transport the landfill gases from thelandfill to the facility if economically feasible. A gas collectionsystem is positioned within the landfill and connects to the pipingsystem. Such gas collection systems typically comprise a series ofperforated pipes or conduits and are known in the art. In FIG. 1, anexample of an entire system that can be positioned on site comprises theLand-Fill Gas (LFG) collection points and a main gas header to separatewaste gases (that are then usually flared, although even this low energyfuel source could be used as energy within the system, even reducingexisting polluting levels by cleaning the burnt/flared stream). Theseparated gas stream including the carbon dioxide and hydrocarbon gasesis then treated in a system to separate the hydrocarbons gases andcarbon dioxide (in this case shown as a pressure condensation unit orPCU). A portion of the hydrocarbon stream (primarily methane) is thensent to a further condensation unit (methane liquefier) and the carbondioxide is sent to carbon dioxide liquefier (CO₂ Liquifier), preferablywhere energy from a natural gas generator (Genset) provided by burning aportion of the ‘natural gas’ (methane and/or other hydrocarbons) is usedto drive the carbon dioxide liquefaction. Portions of the carbon dioxidestream (either directly from the carbon dioxide stream or from theliquefier) are shown to be directed towards a cleaning facility on site(e.g., in this example, a plastic recycling center). The liquefiedcarbon dioxide is shown as then stored in a CO₂ storage tank andliquefied methane is shown in a liquid natural gas (LNG) storage tank.Shipment or sale of these stored gases can be provided with a weighingstation (Scale) where it can be loaded onto a CO₂ trailer or LNG trailerfor shipping to more distal users. A fuel island is also shown for localuse or tank filling with LNG, as with internal (site internal) cartagevehicles or transportation vehicles.

Upon collection, the landfill gas enters the facility as a single streamand is delivered to a pre-conditioning unit. Depending upon the selectedlandfill or gas collection site, and also dependent on the stage atwhich the selected landfill or gas collection site is producing landfillgas, the composition of the landfill gas may vary. Generally, thelandfill gas has about an equal composition of both methane and carbondioxide, along with a minimal amount of nitrogen and trace amounts ofother gases. An exemplary composition of a landfill gas for use with thepresent invention is listed in the Column under Raw Landfill Gas inTable 1. It should be understood, however, and as is known in the art,that there may be substantial fluctuations in the composition of thelandfill gas, and that such fluctuations are well within the scope ofthe present invention.

The pre-conditioning unit separates the landfill gas into a first streamsubstantially comprising methane, and a second stream substantiallycomprising carbon dioxide. By substantially comprising it is meant thatthe dominant component of each stream comprises at least about 90% ofthe respective stream, by volume. An exemplary composition of themethane stream is listed in the Column under Methane Product in Table 1,while an exemplary composition of the carbon dioxide stream wouldcomprise the carbon dioxide and materials (e.g., hydrocarbons) absorbedtherein. It should be noted that these compositions are for descriptivepurposes only, and that variations of each are well within the scope ofthe present invention. If the composition of the methane stream containsa minimum amount of methane to provide adequate energy upon combustion,a fuel stream is fed from the methane stream to an electrical generatorcapable of being powered by the combustion of the methane. Theelectrical generator is provided to generate a minimum amount ofelectricity to power the facility and any action taking place within thefacility, including the collection of the landfill gases, vehicle travelwithin or near the site, making the facility self-reliant, independentof outside power sources. Thus, the minimum amount of methane needed toprovide adequate energy to the facility is dependent upon the size ofthe facility and the type of electrical generator being used. If thecomposition of the methane stream is not great enough to provideadequate energy upon combustion for the electrical generator to powerthe facility, the methane stream must first be enriched. Flue gases fromthe electrical generator can be vented to the atmosphere or routed backthrough the pre-conditioning unit to separate unspent methane and carbondioxide. Scrubbers can be added to remove other combustion gases,including nitrous oxides and carbon monoxides.

Regardless if upon exiting the pre-conditioning unit the methane streamis suitable for combustion within the electrical generator, in mostsituations the methane stream will have to be enriched in order to matchthe quality of natural gas obtained by more conventional methods. Themethane stream connects to a methane enriching unit, which is positioneddownstream from the pre-conditioning unit. The methane enriching unitfurther enhances the methane properties of the methane stream byseparating out non-methane components, including carbon dioxide,nitrogen and other trace components. Upon exiting the methane enrichingunit, the enriched methane stream preferably has a methane content ofabout 97%, by volume. An exemplary composition of the enriched methanestream is listed in Table 4. TABLE 4 % By Volume Material  98% Methane0.5% Oxygen 0.3% Nitrogen 0.2% CO₂ 1.0% Other

At this concentration, the methane is suitable for most industrialapplications. The enriched methane is then either left in a gaseousstate or condensed to compressed natural gas or liquid natural gas forfurther processing. It is desirable to have low oxygen content in thisenriched methane stream. This can be accomplished by the use ofsemipermeable membranes or absorptive materials that selectively removeoxygen from the stream.

One such process is the production of carbon blacks, or gas black.Carbon blacks are used to reinforce rubber products such as tires and asreducing materials in metallurgic industries. Carbon blacks are anamorphous form of carbon particles formed by the thermal or oxidativedecomposition of methane. A preferred process for forming the carbonblacks of the present invention includes the Kvaemer Carbon Black andHydrogen Process, which produces both carbon black and hydrogen withoutemissions. The Kvaemer process is a plasma process for forming carbonblacks and hydrogen. However, other processes for forming carbon blacksare well within the scope of the present invention, including a channelblack method, a lamp black method, a furnace black method and a thermalblack method, all terms known in the art. Both the carbon blacks and thehydrogen can be sold wholesale as commodities.

In addition to carbon blacks, excess methane can be used in otherprocesses to form hydrogen. One such process is steam methane reforming(SMR). In the SMR method, water in the form of steam is combined withmethane to form hydrogen and carbon monoxide or other reformingprocesses. The carbon monoxide shifts to form carbon dioxide andhydrogen. The hydrogen can be captured and used to help generate powerto heat the steam, with the excess being sold as a commodity. The steammay also be used for thermal heating at the facility by cycling thesteam or condensed steam (hot water) through radiator pipes at thefacility.

Also positioned downstream from the pre-conditioning unit is acondensing unit to liquify the carbon dioxide stream. The carbon dioxidecondensing unit connects to a storage tank wherein the liquified carbondioxide is sent. From the storage tank, the liquified carbon dioxide canbe sent to transportation tanks for sale in industrial uses.Alternatively, and more preferably, the liquid carbon dioxide isutilized on-site in the cleansing of substrate materials. In thepractice of the present invention, both of these processes, as well asother processes, may be practiced on site.

Provided within or proximate the facility of the present invention is acleaning apparatus. The cleaning apparatus utilizes liquid carbondioxide to facilitate the removal of contaminants from the substratematerials. The preferred cleaning apparatus is similar to those fullydescribed in U.S. Pat. No. 5,904,737, U.S. Pat. No.6,216,302, U.S. Pat.No.6,257,282, U.S. Pat. No. 6,349,947, and U.S. Pat. No. 6,442,980, allof which are hereby incorporated herein by reference. It should benoted, however, that other cleaning apparatuses, including thosemanufactured by Sailstar, Electrolux and Alliance are well within thescope of the present invention. Preferably, the substrate materialincludes plastics gathered from used or recycled containers. Suchplastics include, but are not limited to, polyethylene (especially highdensity polyethylene “HDPE,” low density polyethylene “LDPE”),polyethylene terephthalate (PET) and polyvinyl chloride (PVC). In manycommunities, the plastic containers are separated from refuse byconsumers and are collected by recycling centers to be reprocessed intonew forms. In other situations, the plastic containers are separated atthe landfill, or even mined from within the landfill. Extraction of thecontaminants, such as motor oil, from the containers typically resultsin acquiring two marketable products: recycled plastics and sometimesusable oil. The preferred extraction process is identical to thatdisclosed in U.S. Provisional Application No. 60/420,017, filed on Oct.21, 2002 and entitled Extraction Process Utilizing Liquified CarbonDioxide, which is hereby incorporated herein by reference. Afterextracting the oil from the substrate material, the plastics can sold inbulk to plastic processing facilities for reuse or even deposited withinthe landfill without the possible harm of contaminating the soil withoil. The oil extracted from the plastics is removed from the solvents,collected and may be sold as a commodity or as a fuel.

Alternatively, other extraction processes utilizing carbon dioxide arewell within the scope of the present invention. Such process include,but are not limited to, the following: processes employing carbondioxide as a solvent or co-solvent; processes employing liquid carbondioxide as a solvent or co-solvent; processes employing super criticalcarbon dioxide as a solvent or co-solvent; and processes employing anycombination of carbon dioxide, liquid carbon dioxide or super criticalcarbon dioxide as a solvent or co-solvent. In addition to the cleaningof plastics, the process of the present invention can be applied toother materials including, but not limited to, other refuse materialsbrought to be deposited into the landfill that contain contaminantscapable of being removed by carbon dioxide, ‘e-waste’ such as boards andmaterials from computers, microprocessors, cellular phones, CRTmonitors, and dry-cleaning facilities. The CO₂ cleaning processes thatmay be used with usable wastes in the practice of the invention may alsobe used in the cleaning of glass and ceramic surfaces. Glass is aparticularly desirable surface to be cleaned in this manner as thetreatment may both clean and polish glass surfaces.

It is important to recognize that the total economic potential oflandfill systems, sewage treatment plants, fertilizer plants, and animalwaste collection sites (which are collectively referred to hereingenerically as ‘gas stream sites’ or ‘waste sites’) have not beenrealized. In large part this is because there has been no considerationof the collective use of the waste streams. Even the pilot attemptdescribed above in methanol conversion basically has provided littlemore than a break even economic flow in the production of methanol. Itis therefore a benefit of the present system that multiple uses ofmultiple streams can be effected, rather than merely working one or twosingle streams for a narrow use. For example, the following combinationsof processes can be combined in a single operating site. A single siteis defined in the practice of the present invention where gas flows fromthe waste site are directly carried to the process streams through adirect piping stream. A direct piping stream would include addition ofmethane to a local gas stream (metering the input to the local stream)and withdrawing gas downstream for a process stream, the volumewithdrawn for the process stream being compared to the addition volumeto determine user costs and contributions.

The present invention may use the hydrocarbon gas stream to produceenergy for multiple uses of both the hydrocarbon gas stream and thecarbon dioxide stream, and by positioning recycling facilities orseparation facilities adjacent the gas stream site, the energy andproducts of the at least three gas streams can be used in a more unifiedefficiency and provide significant economic improvement to the entiresystem. Considered in this perspective, the association of differentprocesses as set forth below is more than a mere collection ofdissimilar processes, but an integration of processes to maximize use ofmaterials and economies.

One example of a combined process system operating off at least threegas streams previously identified could be selected from the groupsconsisting of at least all of the process described, along withadditional processes that can be added into the flow of the gas streamsfrom the gas stream site:

-   -   1) energy production, carbon black production, and hydrogen        production;    -   2) energy production, carbon dioxide liquifaction (including        supercritical liquid formation), and apparel cleaning;    -   3) energy production, carbon dioxide liquifaction (including        supercritical liquid formation), and plastic cleaning;    -   4) energy production, carbon dioxide liquifaction (including        supercritical liquid formation), plastic cleaning and        pellitization of cleaned plastic;    -   5) energy production, carbon dioxide liquifaction (including        supercritical liquid formation), plastic cleaning, plastic        pellitization, and plastic molding or extrusion (e.g.,        structural beam plastic, plastic sheeting, plastic poles,        plastic tubing, etc.);    -   6) energy production, carbon dioxide liquification (including        supercritical liquid formation), and aluminum cleaning;    -   7) energy production, carbon dioxide liquification (including        supercritical liquid formation), aluminum cleaning, and cleaned        aluminum ingot/sheeting formation;    -   8) energy production, carbon dioxide liquification (including        supercritical liquid formation), and glass/ceramic cleaning; and    -   9) energy production, carbon dioxide liquification (including        supercritical liquid formation), glass cleaning and glass        melting processes.        In the performance of these processes, the system has been shown        to be able to exceed the traditional break even points of the        economics of waste sites and gas stream sites that have limited        their success. The performance of at least the processes as        grouped, and the addition of other processes from the other        groups, particularly at a single site where transportation costs        from process to process are reduced or eliminated can provide a        gas stream site that can exceed mere survivability and produce a        significant positive cash flow while improving waste utilization        and increasing the benefits from recycling.

Such new process steps as pumping some carbon dioxide (with water added)back into the land fill through tubes or pipes can increase gasproduction rates, again using waste stream gas to improve the economicsof the total system. The carbon dioxide used in this gas stimulationstream can be recycled from other processes, such as a cleaning process,or from a waste gas stream cleaning scrubber (e.g., from the burning ofhydrocarbons) to further minimize external additions of materials,energy, or capital to the system.

One particularly desirable system would be establishing an apparelcleaning site proximal to the source of the at least three gas streams.Energy from burning a portion of the hydrocarbon can be used to power atleast some of the energy requirements for carbon dioxidecondensing/liquefaction, carbon dioxide-based apparel cleaning,recondensation/purification of the effluent stream of carbon dioxidefrom the apparel cleaning. The effluent carbon dioxide stream can beused, as described above, to stimulate hydrocarbon gasventing/collection/production in the gas stream site.

The waste materials to be recycled or treated may be first prepared by anumber of pretreatments. These pretreatments may include, by way ofnon-limiting examples, water wash or spray, cutting/shredding, soaking,solvent soaking, cosolvent soaking, agitation with or withoutsolvent/cleaner present), sonication in solvent/carrier, coheattreatments with solvents, and the like.

A non-limiting list of solvent systems for removal of label stock inpolymeric container recycling includes a mixture (5:95% by volume to95-5% by volume) of at least one cosolvent selected from the groupconsisting of terpene alcohol, d-Limonene, and isoparaffinichydrocarbons and at least a second cosolvent selected from the groupconsisting of C1-C6 alkyl lactates (especially C1, C2, C3 and C4 alkyllactates, such as methyl lactate, ethyl lactate, propyl lactate andbutyl lactate). Such materials are commercially available as a terpenealcohol based solvent such as environmentally safe Tarksolg, made byTarksol, Inc., d-Limonene (Chemical Abstract Series No. 5989-27-5), orisoparaffinic hydrocarbon (Chemical Abstract Series No. 64742-48-9).These solvents may be used on the label containing (preferably shredded)polymeric materials according to the teachings of U.S. Pat. No.6,514,353, which teaches the use of only the first set of solvents aslabel removing materials. That patent is incorporated by reference forits teachings of solvent application processes, apparatus and materials.

D-limonene is known in certain cleansing solutions such as taught byDotolo et al. (U.S. Pat. No. 5,346,652) describe a non-aqueousfingernail polish remover based upon a d-limonene, N-methyl pyrrolidone(abbreviated NMP), and cetyl acetate solvent system. However, d-limoneneis harmful if swallowed, can be irritating, causes drying, reddening,and sensitization of the skin, and is moderately to highly irritating tothe eyes (MSDS, d-limonene, Florida Chemical Co., Inc., Winter Haven,Fla.). Similarly, Bayless (U.S. Pat. No. 5,372,742) describes anon-aqueous liquid cleaner suited for removing nail polish, based upond-limonene, ethyl lactate, and cetyl acetate. The use of this novelcosolvent-based carbon dioxide, polymer-cleaning system (particularlyfor the removal of labels) is novel in its own right.

As a separate site or in addition to other process plants establishedusing at least a portion of the at least three gas streams would be apolymer material recycling/cleaning/reforming system. The polymercleaning system may include carbon dioxide cleaning of the polymericmaterials, pellitizing of the clean solid polymer, and even molding orreforming of the pelletized polymer, using at least in-part energy fromthe burning of hydrocarbon gas from the at least three gas streams.Solvents may also be added to the carbon dioxide to assist in removinggrease, oils, paints, labels and other materials that should not berecycled with the polymer. A preferred solvent system for removal oflabel stock in polymeric container recycling includes a mixture (5:95%by volume to 95-5% by volume) of at least one cosolvent selected fromthe group consisting of terpene alcohol, d-Limonene, and isoparaffinichydrocarbons and at least a second cosolvent selected from the groupconsisting of C1-C6 alkyl lactates (especially C1, C2, C3 and C4 alkyllactates, such as methyl lactate, ethyl lactate, propyl lactate andbutyl lactate). Such materials are commercially available as a terpenealcohol based solvent such as environmentally safe Tarksol®, made byTarksol, Inc., d-Limonene (Chemical Abstract Series No. 5989-27-5), orisoparaffinic hydrocarbon (Chemical Abstract Series No. 64742-48-9).These label cleaning cosolvent systems are proprietary to assignee andthe subject of a copending patent application bearing Attorney's docketnumber 590.002US 1. These solvents may be used on the label containing(preferably shredded) polymeric materials according to the teachings ofU.S. Pat. No. 6,514,353, which teaches the use of only the first set ofsolvents as label removing materials. That patent is incorporated byreference for its teachings of solvent application processes, apparatusand materials.

D-limonene is known in certain cleansing solutions such as taught byDotolo et al. (U.S. Pat. No. 5,346,652) describe a non-aqueousfingernail polish remover based upon a d-limonene, N-methyl pyrrolidone(abbreviated NMP), and cetyl acetate solvent system. However, d-limoneneis harmful if swallowed, can be irritating, causes drying, reddening,and sensitization of the skin, and is moderately to highly irritating tothe eyes (MSDS, d-limonene, Florida Chemical Co., Inc., Winter Haven,Fla.). Similarly, Bayless (U.S. Pat. No. 5,372,742) describes anon-aqueous liquid cleaner suited for removing nail polish, based upond-limonene, ethyl lactate, and cetyl acetate. The use of this novelcosolvent-based carbon dioxide, polymer-cleaning system (particularlyfor the removal of labels) is novel in its own right.

In addition to the cosolvent or individual solvent systems used with orwithout carbon dioxide cleaning in the described technology, additionalsolvents or cleaners may be added to the system with varying benefits ordistractions. Among these are terpenes, halohydrocarbons, certain glycolethers, polyols, ethers, esters of glycol ethers, esters of fatty acidsand other long chain carboxylic acids, fatty alcohols and otherlong-chain alcohols, short-chain alcohols, polar aprotic solvents,siloxanes, hydrofluoroethers, dibasic esters, and aliphatic hydrocarbonssolvents or similar solvents or mixtures of such solvents are organicsolvents that can be used in the present technology. TABLE 1 GASANALYSIS REPORT by Atlantic Analytical Laboratory (AAL, Whitehouse, NJ)ACRION'S CO2 WASH PROCESS DEMONSTRATION UNIT NJ ECOCOMPLEX/BURLINGTONCOUNTY LANDFILL/ September 2001 Raw Landfill Gas Methane Product ppmvolume DL ppm ppm volume DL ppm Non-Condensable Gases Nitrogen 6.7 0.019.6 0.01 Oxygen 0.10 0.10 Hydrogen 0.10 0.10 Carbon Dioxide 35.0 0.0125.7 0.01 Volatile Hydrocarbons Methane 49.6% 1 −62.6% 1 Ethylene 3 1 31 Acetylene Nd 10 nd 10 Ethane 2 1 2 1 Propylene Nd 1 nd 1 Propane 41 114 1 Isobutane 13 1 1 n-Butane 8 1 nd 1 Butenes Nd 1 nd 1 Isopentane 2 1nd 1 n-Pentane 2 1 nd 1 Hexanes 200 1 nd 1 Volatile Sulfur CompoundsHydrogen Sulfide Nd nd 0.05 Carbonyl Sulfide 1.10 0.1 0.05 SulfurDioxide Nd nd 0.05 Methyl Mercaptan Nd nd 0.05 Ethyl Mercaptan Nd nd0.05 Dimethyl Sulfide 4.00 nd 0.05 Carbon Disulfide 0.46 nd 0.05Isopropyl Mercaptan Nd nd 0.05 Methyl Ethyl Sulfide 0.06 nd 0.05n-Propyl Mercaptan Nd nd 0.05 t-Butyl Mercaptan 0.26 nd 0.05 DimethylDisulfide 1.00 nd 0.05 sec-Butyl Mercaptan 0.16 nd 0.05 IsobutylMercaptan 0.26 nd 0.05 Diethyl Sulfide Nd nd 0.05 n-Butyl Mercaptan 0.12nd 0.05 GC/MS Results TO-14 Target List Freon-12 2.8 nd 0.5 MethylChloride Nd 0.5 nd 0.5 Freon-114 0.5 nd 0.5 Vinyl Chloride 0.5 nd 0.5Methyl Bromide Nd 0.5 nd 0.5 Ethyl Chloride Nd 0.5 nd 0.5 Freon-11 Nd0.5 nd 0.5 Vinylidene Chloride Nd 0.5 nd 0.5 Freon-113 Nd 0.5 nd 0.5Dichloromethane Nd 0.5 nd 0.5 1,1-Dichlorethane Nd 0.5 nd 0.5cis-1,2-Dichloroethylene 1.2 nd 0.5 Chloroform Nd 0.5 nd 0.51,1,1-Trichloroethane Nd 0.5 nd 0.5 1,2-Dichlorethane Nd 0.5 nd 0.5Benzene 0.8 nd 0.2 Carbon Tetrachloride Nd 0.5 nd 0.51,2-Dichloropropane 5.1 nd 0.5 Trichloroethylene 0.7 nd 0.2 cis-1,3-/ Nd0.5 nd 0.5 Dichloropropylene trans-1,3- Nd 0.5 nd 0.5 DichloropropyleneToluene 38.0 nd 0.2 1,1,2-Trichloroethane Nd 0.2 nd 0.21,2-Dibromoethane Nd 0.5 nd 0.5 Tetrachloroethylene 1..5 nd 0.2Chlorobenzene Nd 0.2 nd 0.2 Ethyl Benzene 14.0 nd 0.2 m+p-Xylenes 15.0nd 0.2 Styrene 4.4 nd 0.2 o-Xylene 4.2 nd 0.2 1,1,2,2- Nd 0.2 nd 0.2Tetrachloroethane 4-Ethyltoluene 6.2 nd 0.2 1,3,5-Trimethylbenzene 1.2nd 0.2 1,2,4-Trimethylbenzene 1.2 nd 0.2 1,3-Dichlorobenzene Nd 0.2 nd0.2 1,4-Dichlorobenzene Nd 0.2 nd 0.2 Benzylchloride Nd 0.2 nd 0.21,2-Dichlorobenzene Nd 0.2 nd 0.2 1,2,4-Trichlorobenzene Nd 0.2 nd 0.2Hexachlorobutadiene Nd 0.2 nd 0.2 GC/MS Results Non-TO-14 Target ListPropane 41 14 Isobutane 13 nd 0.5 Acetone 21 nd 0.5 Methylethyl Ketone40 nd 0.5 2-butanol 38 nd 0.5 C6H12O2 28 nd 0.5 C9 Aliphatic 32 nd 0.5Hydrocarbon Alpha-Pinene 38 nd 0.5 C11 Aliphatic 16 nd 0.5 HydrocarbonD-Limonene 15 nd 0.5 GC/MS Results Toxic Substances Sub-17 Freon 12 nd10 Vinyl Chloride nd 10 Chloroform nd 10 1,2-Dichloroethane nd 10Benzene nd 10 Carbon Tetrachloride nd 10 Trichloroethylene nd 101,4-Dioxane nd 10 1,1,2-Trichloroethane nd 10 1,2-Dibromoethane nd 10Tetrachloroethylene nd 10 1,1,2,2 Tetrachloroethane nd 10 MethyleneChloride nd 10 1,1,1-Trichloroethane nd 10NOTES:AAL 6061-1: raw landfill gas after compression to 400 psig and waterknockoutAAL-6061-3: product gas from CO2 washDL = Detection Limit, if not shown, reported result is greater than DLnd = concentration is less than stated DL— = test not performedppm = parts per millionppb = parts per billion

Any form of landfill source or other solids disposal site can be used inthe practice of the present invention, including by way of non-limitingexamples, area landfills, trench landfills, and ramp landfills. Thelandfills may be lined or unlined, although lined landfills (with clayor polymeric materials) are predominant in modern constructions.Preferred are municipal solid waste (MSW) landfills with restrictions orabsolute exclusions on the presence of toxic waste materials.

MSW landfills may be segmented into cells, with distinct time frames ofwaste present in distinct cells or separate compartments of the site.LFG collection may be distinct from each cell, and where undesirable(e.g., toxic) emissions are found in one cell, source of the landfillgas may be switched to another site. Also, as a cell emission ratediminishes, LFG collection may be readily shifted to another cell,allowing the tired site to ‘refresh’ and recover so that it can emit ata satisfactory rate at a later time. This will maximize removal of gasfrom each cell and each landfill site. FIG. 5 shows a unique approach tothe cleaning operation, recycling operation and energy conservation.

A liquefied gas cleaning system is provided in which a refrigerationsystem is used to re-condense the gaseous solvent to a liquid. Thecondensation occurs in the cooled section of the condenser the gaseoussolvent is evaporated (leaving behind waste material picked up duringcleaning operations) in the heated section of the condenser. Therefrigeration system may by way of example, consist of a compressor, anexpansion valve, and a heat exchanger. The heat exchanger is cooled bythe liquid gas in a pressurized tank. The heat causes the liquid(solvent) to boil (or otherwise evaporate), thereby distilling theliquid and providing clean liquid (solvent). Also, in a two solventcleaning system, (first solvent pre-wash, then second cleaning with apressurized fluid), an additional heat exchanger could be placed in thefirst wash solvent to warm the solvent for better cleaning performance(reference is made to U.S. Pat. No. 6,558,432 which is incorporatedherein by reference for that background technology). A final air heatexchanger may be used if the refrigeration system coolant is not cooledenough by the first two heat exchangers. The cold side of therefrigeration system can be used to re-condense the distilled gaseoussolvent back to the liquid phase. This process can take place in twoseparate tanks, or in the same tank. FIG. 5 shows the process occurringin two tanks. The liquefied gas solvent could be carbon dioxide,propane, etc.

FIG. 6 shows a schematic of one possible embodiment of a completecooling system VI according to the present invention. The cooling systemVI comprises a vacuum insulated storage tank 200 for storing liquidcarbon dioxide. The carbon dioxide is passed through tube system 202into other elements of the system such as an isolation valve IV,pressure gauge PG, pressure transmitter PT, liquid level transmitter LLT(which senses variations in pressure between the top of the tank andbottom of the tank, giving an indication of the height of liquid withinthe tank), supplemental release valve SLV, backpressure regulator 204,line releases LR, check valves 208, the like. One of a number offunctions that can be provided by the system of FIG. 6, in addition tocleaning can be described as follows.

When carbon dioxide liquid is replenished into a tank 200 as in thecleaning system VI, gaseous carbon dioxide has been traditionallyvented, as its presence in the tank prevents complete filling of thetank. In the present sequent of steps that forms a novel process, thegaseous carbon dioxide is vented through 202 into the cleaning wheelarea 212, where in a separate process or separate step, liquid carbondioxide is added as the cleaning solvent. In this case, the wheel storesvented carbon dioxide which can be transmitted via a carbon dioxidecompressor 222 into the top of cooling (liquefying) tank 230, and/orthrough still 242 to the carbon dioxide condenser 222 into the top ofthe cooling tank 230 or through filter (e.g., carbon black) media 246and then into the top of the cooling tank 230. In this manner, ventedcarbon dioxide from the primary storage tank can be used as a source ofliquid carbon dioxide. It is also possible to vent the gaseous carbondioxide and recirculate the carbon dioxide as cooled liquid from coolingtank 230 (which may have a water cooling system such as shown 238) orhave it stored in the cooling tank 230. The wheel or drum cleaner 212may thus be used as a storage tank for vented carbon dioxide in oneprocess or one step of a larger systemic process, and then be used asthe solvent scrubbing chamber at another time in the systemic process.

The wheel drum 212 agitates the ground plastic and carbon dioxide whichis drawn through pipes 213 for cleaning. The motor 244 powers therotation of the drum. Portions of the carbon dioxide stream (which isnow contaminated with material) can be vented through pipes 213 are sentthrough various control valves into the filter 246,and/or thec0ondensing system 248 and 222, and/or the cooling tank 230 comprising awater chiller 238 and condensing coils 240 to condense and chill thecarbon dioxide to assist in forming additional liquid cleaner gradecarbon dioxide from the vented carbon dioxide. Cleansed carbon dioxidecan be recycled through valves back to the wheel drum during a cleaningcycle.

Although specific examples and constructions and materials have beenused to emphasize the generic concepts of the present invention, theseare intended to be non-limiting examples, and not to be absolute limitsin the scope of practice of the invention. Alternatives, variations anddifferences will be understood by those of ordinary skill in the artwithin the scope of the technology described.

1. A process for use of gases collected from a solid/liquid materialwaste site comprising: collecting gases from the material waste siteseparating the collected gases into at least three streams comprising ahydrocarbon stream, a carbon dioxide stream, and residue stream,condensing at least a portion of the carbon dioxide stream orhydrocarbon stream to a liquid or supercritical liquid, using at least aportion of the hydrocarbon stream to generate energy, and using energyfrom the hydrocarbon stream to power a commercial process comprisingcleaning with carbon dioxide as a cleaning material and optionally atleast one process selected from the group consisting of carbon dioxideliquefaction, hydrogen production, carbon black production, cleaningwith carbon dioxide as a cleaning material, molding polymeric materials,and pelletizing polymeric materials; wherein prior to cleaning withcarbon dioxide, material to be cleaned is exposed to a solventcomprising at least one C1-C₆ alkyl lactate.
 2. The process of claim 1wherein the solvent comprises a cosolvent system comprising at least onefirst cosolvent selected from the group consisting of terpene alcohol,d-Limonene, and isoparaffinic hydrocarbons and the least one cosolventselected from the group comprising of C1-C₆ alkyl lactate.
 3. Theprocess of claim 2 wherein the solid material waste site comprises alandfill.
 4. The process of claim 3 wherein the commercial processincludes at least on-site cleaning use of liquid carbon dioxide orsupercritical carbon dioxide.
 5. The process of claim 2 wherein thecommercial process includes using liquid carbon dioxide or supercriticalcarbon dioxide in a polymeric material cleaning process.
 6. The processof claim 3 wherein the commercial process includes using liquid carbondioxide or supercritical carbon dioxide in a polymeric material cleaningprocess that is part of a solid polymer recycling process.
 7. Theprocess of claim 3 wherein the commercial process includes using liquidcarbon dioxide or supercritical carbon dioxide in a polymeric materialcleaning process that is part of a polymer recycling process whereinventing of gases, separating of gases into at least three streams,burning of a portion of the hydrocarbon stream, and use of energy fromburning to power a process that takes place within an 18 km radius fromthe separation of gases into at least three gas streams.
 8. The processof claim 6 wherein the commercial process includes using liquid carbondioxide or supercritical carbon dioxide in a polymeric material cleaningprocess that is part of a polymer recycling process wherein venting ofgases, separating of gases into at least three streams, burning of aportion of the hydrocarbon stream, and use of energy from burning thehydrocarbon stream in a process that takes place within an 18 km radiusfrom the separation of gases into at least three gas streams.
 9. Theprocess of claim 7 wherein plastic is reduced in size to smallersegments of solid plastic during the polymer recycling process, and thesmaller segments of plastic are cleaned with carbon dioxide from thecarbon dioxide stream.
 10. The process of claim 9 wherein the carbondioxide stream used to clean the smaller segments comprisessupercritical liquid carbon dioxide.
 11. The process of claim 10 whereina solvent is used to remove material from the smaller segments ofpolymer in advance of or at the same time as the use of carbon dioxideused to clean the smaller segments of polymer.
 12. The process of claim11 wherein the solvent is an organic solvent to assist in the dissolvingof adhesive or glue on the smaller segments of polymer.
 13. The processof claim 1 wherein at least some hydrocarbon gas is used in a carbonblack production process.
 14. A system of combined processes, incombination with at least one carbon dioxide cleaning process, at leastone of the combined processes operating from a power source of at leastthree gas streams from a waste gas stream site are selected from thegroup consisting of: a) energy production, carbon black production, andhydrogen production; b) energy production, carbon dioxide liquification,supercritical or liquid carbon dioxide formation, and apparel cleaning;c) energy production, carbon dioxide liquification, supercritical orliquid carbon dioxide formation, and plastic cleaning; d) energyproduction, carbon dioxide liquification, supercritical or liquid carbondioxide formation, plastic cleaning and pellitization of cleanedplastic; e) energy production, carbon dioxide liquification,supercritical or liquid carbon dioxide formation, plastic cleaning,plastic pellitization, and plastic molding or extrusion; f) energyproduction, carbon dioxide liquification, supercritical or liquid carbondioxide formation, and aluminum cleaning; g) energy production, carbondioxide liquification, supercritical or liquid carbon dioxide formation,aluminum cleaning, and cleaned aluminum ingot/sheeting formation; h)energy production, carbon dioxide liquification, supercritical or liquidcarbon dioxide formation, and glass/ceramic cleaning; and i) energyproduction, carbon dioxide liquification, supercritical or liquid carbondioxide formation, glass cleaning and glass melting processes, j) energyproduction, carbon dioxide liquification, supercritical or liquid carbondioxide formation and solvent distillation processes wherein energyproduction comprises providing at least some energy derived fromcombustion of hydrocarbon gases from at least one of said three gasstreams; and wherein in the cleaning process prior to cleaning withcarbon dioxide, material to be cleaned is exposed to a solventcomprising at least one C₁-C₆ alkyl lactate and then exposed to thecleaning carbon dioxide.
 15. The system of claim 14 wherein the solventcomprises a cosolvent system comprising at least one first cosolventselected from the group consisting of terpene alcohol, d-Limonene, andisoparaffinic hydrocarbons and the least one cosolvent selected from thegroup comprising of C₁-C₆ alkyl lactate.
 16. The system of claim 14where the waste gas stream site comprises a site having distinct cellsof landfill waste mass and controls are present so that waste gas streamsites may be opened and closed from selected cells to control waste gasflow through the system.
 17. The system of claim 16 where the waste gasstream site comprises a site having distinct piping to areas of alandfill waste site and controls are present so that waste gas streamsites may be opened and closed from selected areas of the landfill wastesite to control waste gas flow through the system.
 18. A process for thecleaning of waste polymeric material comprising: providing solid polymermaterial, reducing the size of the solid polymeric material intosegments of solid polymeric material, at least surface contacting thesegments of solid polymeric material with a cleaning solvent, removingcleaning solvent to provide partially cleaned segments of solidpolymeric material, and cleaning the partially cleaned segments of solidpolymeric material with densified carbon dioxide; wherein the solventcomprises a solvent comprising C₁-C₆ alkyl lactate or a cosolvent systemcomprising at least one first cosolvent selected from the groupconsisting of terpene alcohol, d-Limonene, and isoparaffinichydrocarbons and the least one second cosolvent selected from the groupcomprising of C₁-C₆ alkyl lactate.
 19. The process of claim 18 whereinthe densified carbon dioxide comprises liquid carbon dioxide orsupercritical carbon dioxide.
 20. The process of claim 19 wherein thesolid polymeric material comprises polymeric material having labelmaterial adhered thereto.
 21. A liquefied-gas cleaning system in whichgas cleaning material is recycled within the system comprising: aliquefied-gas cleaner storage tank; a vent from the liquefied-gascleaner storage tank to assist in conveying gas phase of the liquidcleaner to a cleaning region when the cleaning region is not cleaningwith liquid gas so that vented gas may be stored as stored gas, a secondventing system for transporting stored gas to a cooling tank where gascleaner is cooled to a liquid as recycled liquefied gas and a furtherconveying system by which recycled liquefied-gas is introduced into thecleaning tank as a cleaning solvent or is placed into the liquefied-gascleaner storage tank.
 22. A liquefied-gas cleaning system in combinationwith the system of claim 14 in which gas cleaning material is recycledwithin the system comprising: a liquefied-gas cleaner storage tank; avent from the liquefied-gas cleaner storage tank to assist in conveyinggas phase of the liquid cleaner to a cleaning region when the cleaningregion is not cleaning with liquid gas so that vented gas may be storedas stored gas, a second venting system for transporting stored gas to acooling tank where gas cleaner is cooled to a liquid as recycledliquefied gas and a further conveying system by which recycledliquefied-gas is introduced into the cleaning tank as a cleaning solventor is placed into the liquefied-gas cleaner storage tank.
 38. A systemof combined processes operating from a source of at least three gasstreams from a waste gas stream site are selected from the groupconsisting of: k) energy production, carbon black production, andhydrogen production; l) energy production, carbon dioxide liquification,supercritical or liquid carbon dioxide formation, and apparel cleaning;m) energy production, carbon dioxide liquification, supercritical orliquid carbon dioxide formation, and plastic cleaning; n) energyproduction, carbon dioxide liquification, supercritical or liquid carbondioxide formation, plastic cleaning and pellitization of cleanedplastic; o) energy production, carbon dioxide liquification,supercritical or liquid carbon dioxide formation, plastic cleaning,plastic pellitization, and plastic molding or extrusion; p) energyproduction, carbon dioxide liquification, supercritical or liquid carbondioxide formation, and aluminum cleaning; q) energy production, carbondioxide liquification, supercritical or liquid carbon dioxide formation,aluminum cleaning, and cleaned aluminum ingot/sheeting formation; r)energy production, carbon dioxide liquification, supercritical or liquidcarbon dioxide formation, and glass/ceramic cleaning; and s) energyproduction, carbon dioxide liquification, supercritical or liquid carbondioxide formation, glass cleaning and glass melting processes, t) energyproduction, carbon dioxide liquification, supercritical or liquid carbondioxide formation and solvent distillation processes wherein energyproduction comprises providing at least some energy derived fromcombustion of hydrocarbon gases from at least one of said three gasstreams where the waste gas stream site comprises a site having distinctcells of landfill waste mass and controls are present so that waste gasstream sites may be opened and closed from selected cells to controlwaste gas flow through the system wherein at least some carbon dioxidefrom a carbon dioxide stream is used in a polymeric cleaning process,and cleaned polymer from the polymer cleaning process is palletized andlabel removed from palletized polymer using a cosolvent systemcomprising at least a first cosolvent selected from the group consistingof terpenes, D-limonene and parafinnic hydrocarbons, and at least onesecond cosolvent selected from the group consisting of C1-C6 alkyllactates; and; carbon dioxide cleaning material is recycled within acleaning and recycling portion of the system that comprises: a liquefiedcarbon dioxide storage tank; a vent from the liquefied carbon dioxidestorage tank to assist in conveying a gas phase of the carbon dioxidecleaning material to a cleaning region when the cleaning region is notin a cleaning mode with liquid gas so that vented gas may be stored asstored gas, a second venting system for transporting stored gas to acooling tank where gas cleaner is cooled to a liquid as recycledliquefied carbon dioxide and a further conveying system by whichrecycled liquefied carbon dioxide is introduced into the cleaning tankas a cleaning solvent or is placed into the liquefied carbon dioxidestorage tank.